System And Method Of Detecting And Locating Intermittent And Other Faults

ABSTRACT

Data associated with at least one building condition or status is sensed by one or more sensors. The data from these sensors may be sent over a data bus and received by the central computer. In addition, a modulated signal may be transmitted by one or both of the transmitters across the data bus. The modulated signal is received at the receiver, which analyzes the received modulated signal, and determines whether an intermittent fault has occurred on the data bus based upon the analyzing. For example, the receiver may compare the received signal to an expected pattern and when a discrepancy exists, an intermittent fault is determined to exist. The receiver may also determine the location of the fault based upon the analysis.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.12/464,561 filed May 12, 2009 and entitled “System and Method ofDetecting and Locating Intermittent and Other Faults” naming Charles Kimas an inventor and having Attorney Docket Number 94083, which is acontinuation-in-part of application Ser. No. 12/262,664 filed Oct. 31,2008 and entitled “System and Method of Detecting and LocatingIntermittent Electrical Faults in Electrical Systems” naming Charles Kimas inventor and having Attorney Docket No. 93329, the contents of bothof which are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

This application relates to approaches for detecting and/or locatingelectrical faults in electrical systems or networks.

BACKGROUND

Intermittent electrical faults are physical events that manifestthemselves occasionally and in often unpredictable ways withinelectrical systems or networks. When an intermittent fault occurs in asystem, the system may produce erroneous results or could fail. To takesome specific examples of particular electrical faults that occur innetworks, a wire may rub against a neighboring wire and a smallelectrical arc may be created as a result of the contact. In anotherexample, a clamp may break through the insulation surrounding the wireand touch the wire creating a fault. In yet another example, a wire maybreak at the back end of a connector thereby creating a fault. In stillanother example, corrosion may create intermittent non-contact betweenwires and pins within a given system. In another example, cracks onwires within the system may have water dripping on them (or the wiresmay be in contact with other substances) thereby creating electricalfaults. Internal coil turn-to-turn insulation in electric machines mayalso fail in systems with electrical coils creating electrical faults.

The consequences of intermittent electrical faults can be severe and, inmany instances, can cause substantial damage to the electricalequipment, can result in injury to users, or can even cause the loss ofhuman life. For instance electrical fires may be sparked because of theoccurrence of some electrical faults. When the faults occur in aircraft,fuel tank explosions may occur if electrical faults occur near a fueltank. Even if catastrophic damage or injury does not occur, theoperational lifetime of machines or systems may be reduced as the resultof the occurrence of intermittent electrical faults. One characteristicof intermittent faults is that they are random and unpredictable. Theirrecurrence is also unpredictable. However, if an intermittent fault isleft undetected and un-repaired, a major, disastrous, and permanentfault might follow that may cause deaths, failures, or destruction.

Previous attempts at identifying electrical faults have relied upon thevisual or instrument-aided inspection of electrical systems. However,various disadvantages exist with these previous approaches. For example,the operation of the system frequently had to be suspended to determineif a fault existed thereby causing various problems such as loss ofrevenue for the owner or operator of the system. Moreover, manylocations within existing systems were frequently hard to reach and/orobserve thereby severely limiting the effectiveness of these approaches.These previous approaches also proved unable to detect the fault in manycases since the duration of the fault was often short and the systemwould behave normally as if nothing happened after this short-livedintermittent fault event. Therefore, it was relatively easy for theobserver to miss the occurrence of the fault. Additionally, theseapproaches often relied upon intrusive placement of any equipment usedfrequently leading to at least some disruption of the existing system.

Other previous approaches relied upon transmitting electromagnetic wavesacross the network being observed. In one previous example, pulses weretransmitted in networks and any reflections were analyzed to determineif a fault existed. More specifically, incident standing waves orimpulses were transmitted and then reflected in the network, and thenthe time between the incident pulse and the reflected pulse wascalculated to determine the distance to the location where the pulse wasreflected. Different criteria were then used to determine if thereflection was a potential fault. One problem with this technique wasthat any change in the wire material (e.g., a branch-out in the network)reflected the incident waves resulting in erroneous fault determination.Another problem with this technique was that it required thetransmission of high voltage pulses, which some electrical systems withthin coils (e.g., with short wires or thin windings) could not endure.Another time domain reflectometry method employed spread-spectrumtechniques, but this approach did not solve the above-mentioned problemssince high voltage pulse transmission was still required and reflectionstill occurred on branches of the electrical network.

Another previous approach transmitted direct-sequence spread-spectrummodulated signals, instead of high voltage signals, and employed signalprocessing techniques in an attempt to find and locate electricalfaults. These approaches, however, still relied on reflectometry thatis, sending incident signal and receiving reflected signal and thetiming of them for distance calculation. As a result, although thisapproach may have, under some circumstances, overcome the need to usehigh voltage incident voltage pulses, it still had the problem ofreflection occurring at all points of branching in the network and inthe devices that were connected.

Still another problem of the reflectometry approach was that thelocation of the device must be close to one end of the electricalsystem, either the line end or the source end. Otherwise, the injectedsignal would be reflected from both ends and result in a combined,distorted, and reflected signal. This requirement of locating the deviceat either end is very difficult to meet since many electrical networksare connected in a complicated format, often in a mesh architecture.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 comprises a block diagram of a fault determination systemaccording to various embodiments of the present invention;

FIG. 2 comprises one example of a byte-map for use in a faultdetermination system according to various embodiments of the presentinvention;

FIG. 3 comprises a block diagram and fault determination tableillustrating one approach for fault determination according to variousembodiments of the present invention;

FIG. 4 comprises a block diagram of a fault determination apparatusaccording to various embodiments of the present invention;

FIG. 5 comprises a flow chart of one approach for determining faultsaccording to various embodiments of the present invention;

FIG. 6 comprises a flow chart of one approach for determining faultsaccording to various embodiments of the present invention;

FIGS. 7 a and 7 b comprise a block diagram and a flow chart of oneapproach for determining electrical faults according to variousembodiments of the present invention;

FIG. 8 comprises a block diagram of a transmitter and receiver accordingto various embodiments of the present invention;

FIG. 9 comprises a block diagram of a controller module (e.g., atransmitter or receiver) according to various embodiments of the presentinvention;

FIG. 10 comprises a diagram of a controller module (e.g., a transmitteror receiver) being coupled to a transmission line according to variousembodiments of the present invention;

FIG. 11 comprises a diagram of another example of a controller module(e.g., a transmitter or receiver) being coupled to a electrical networkaccording to various embodiments of the present invention;

FIG. 12 comprises a diagram of another example of controller module(e.g., a transmitter or receiver) being coupled to an electrical networkaccording to various embodiments of the present invention;

FIG. 13 comprises a diagram of a magnetic coupling arrangement accordingto various embodiments of the present invention;

FIG. 14 comprises a diagram of a controller module (e.g., a transmitteror receiver) placed in a wall according to various embodiments of thepresent invention;

FIG. 15 comprises a diagram of a network including controller modules(e.g., transmitters and/or receivers) according to various embodimentsof the present invention;

FIG. 16 comprises a diagram of an example of a transmitter and receiveras used in an optical network according to various embodiments of thepresent invention;

FIG. 17 comprises a diagram of another example of a transmitter andreceiver as used in an optical network according to various embodimentsof the present invention;

FIG. 18 comprises a block diagram of a network including faultdetermination devices according to various embodiments of the presentinvention;

FIG. 19 comprises a diagram of a network including fault determinationdevices according to various embodiments of the present invention;

FIG. 20 comprises a flowchart of another fault determination approachaccording to various embodiments of the present invention;

FIG. 21 comprises examples of modulation approaches for the faultdetermination approaches described herein according to variousembodiments of the present invention;

FIG. 22 comprises a flowchart of a fault determination approachaccording to various embodiments of the present invention.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions and/or relative positioningof some of the elements in the figures may be exaggerated relative toother elements to help to improve understanding of various embodimentsof the present invention. Also, common but well-understood elements thatare useful or necessary in a commercially feasible embodiment are oftennot depicted in order to facilitate a less obstructed view of thesevarious embodiments of the present invention. It will further beappreciated that certain actions and/or steps may be described ordepicted in a particular order of occurrence while those skilled in theart will understand that such specificity with respect to sequence isnot actually required. It will also be understood that the terms andexpressions used herein have the ordinary meaning as is accorded to suchterms and expressions with respect to their corresponding respectiveareas of inquiry and study except where specific meanings have otherwisebeen set forth herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Approaches are provided to detect the presence and locations of faultswithin an electrical or other type of networks (e.g., optical networks).The approaches utilize one or more transmitters to send signals (e.g.,packets) over electrical wires (or other types of conductors thattransmit any type of signal) to one or more receivers via a coupler ineach of these devices. Based upon the mismatch between the signal sentand the signal received at the receiver(s) due to the distortion in thesignal transmission caused by the transient of intermittent fault, thepresence and/or location of electrical (or other types of) faults isdetermined. These coupling arrangements for signal injection andreception can also be made in two split half-couplers. By separating thecoupler into a wire-side half-coupler and an in-controller half-couplerof a transmitter or receiver, the controller can become portable andwirelessly exchange carrier signals with the electrical network via thewire-side half-coupler. The approaches described herein are easy andcost effective to use, do not rely upon the transmission of high voltagesignals, can be installed at any location within the electrical network,are an effective detection solution for the unpredictable intermittentevent of faults that occur between transmitter and receiver, and are notsusceptible to the problems of previous approaches.

In many of these embodiments, a signal is conducted from a controllermodule onto an electrical network via a first magnetic coupling. Thesignal is transmitted across the electrical network and received at oneor more receiver modules via one or more second magnetic couplings. Atthe one or more receiver modules, the received signal is analyzed andbased upon the analysis, a determination is made as to whether a faulthas occurred in the electrical network. The first magnetic coupling andthe one or more second magnetic couplings may each comprise atransformer having a primary winding and a secondary winding.

In some examples, the first magnetic coupling is selectively activatedand deactivated to effect the connection and disconnection of thecontroller module from the electrical network.

In other examples, the signal is transmitted across the network to aplurality of receivers and wherein each of the receiver modules includesa separate magnetic coupling. In other examples, the signal is broadcastto one or more receivers. The signal may be broadcast to differentreceiver module groupings at different times and at differentfrequencies.

Another advantage of the present approaches is that they can be used todetermine and locate faults in any wired network that is disposed at anylocation. For example, these approaches can be utilized in all types ofvehicles (e.g., cars, trucks, ships, aircraft), buildings (e.g.,schools, power plants, homes, offices, across wide areas (e.g., collegecampuses, office parks, cities, countries), and appliances (e.g.,generators, consumer appliances) to mention a few examples.

In others of these embodiments, data associated with at least onebuilding condition or status is sensed by one or more sensors. Forexample, the temperature in a building or whether a door is open orclosed may be sensed. The data from these sensors may be sent over adata bus and received by the central computer or controller. Then, amodulated signal may be transmitted by a transmitter across the databus. Other modulated signals may be transmitted by other transmitters.The modulated signal is received at the receiver, which analyzes thereceived modulated signal, and determines whether an intermittent faulthas occurred on the data bus based upon the analyzing. For example, thereceiver may compare the received signal to an expected pattern and whenthe comparison determines that a discrepancy exists, an intermittentfault is determined to exist. The receiver may also determine thelocation of the fault based upon the analysis.

In other aspects, a modulated signal is transmitted across the power busby other transmitter(s). The modulated signal is received by anotherreceiver and the receiver analyzes the received modulated signal anddetermines whether an intermittent fault has occurred on the power busbased upon the analysis. For example, the receiver may compare thereceived signal to an expected pattern and when a discrepancy exists, anintermittent fault is determined to be present. The receiver may alsodetermine the location of the fault on the power bus based upon theanalysis.

In some of these examples, the modulated signals on the data or powerbuses are transmitted from multiple transmitters to a single receiver.Other configurations are possible (e.g., multiple transmitters tomultiple receives, a single transmitter to single receiver, a singletransmitter to multiple receivers).

In still other aspects, a first modulated signal is transmitted by oneof the transmitters. When the first modulated data signal is received atthe receiver without significant distortion at a receiver, a secondmodulated signal on the data bus is transmitted from one of the sensorsor central computer, or user interface, over the data bus. The secondmodulated signal is received at the receiver and the received secondmodulated signal is analyzed to determine if an intermittent faultexists on the data bus (e.g., by comparing it to an expected pattern).

In yet other aspects, the sensors may be any type of sensing device suchas a temperature sensor, a radioactivity sensor, a motion sensor, apressure sensor, and a humidity sensor. Other examples are possible.

In other aspects, one or more of the sensors that are disposed in thebuilding sense a condition or status associated with the building or anelement associated with the building. A plurality of modulated signalsindicating this information are transmitted via the bus that is disposedin the building. Each of the plurality of modulated signals is modulatedaccording to an approach that avoids interference between each of theplurality of signals. The plurality of modulated signals from the atleast one sensing device are received, for example, at a centralcomputer, and the central computer or controller in the building (orlocated outside the building at a remote location) processes the data inthe received modulated signals.

In other aspects, a modulated signal is transmitted from a transmitterand across the power bus that is coupled to the sensors. The modulatedsignal is received at the receiver and the received modulated signal isanalyzed. A determination is made as to whether an intermittent faulthas occurred on the power bus based upon the analysis. A similarapproach can be used on the data bus to determine if intermittent faultsare present on the data bus.

Various forms of modulation may be used. For example, amplitude shiftkeying (ASK) modulation, frequency shift keying (FSK) modulation, Phaseshift keying (PSK) modulation, Binary shift keying (BSK) modulation,Binary Phase shift keying (BPSK) modulation, quadrature phase shiftkeying (QPSK) modulation, offset quadrature phase shift keying (OQPSK)modulation, minimum shift keying (MSK) modulation, Gaussian minimumshift keying (GMSK), multiple phase shift keying (M-PSK), Π/4 QPSKmodulation may be used. Other examples of modulation are possible.

In other aspects, a vehicle includes one or more sensors are configuredto sense data associated with the vehicle (e.g., interior temperature),a status of the vehicle (e.g., vehicle moving), or an element of thevehicle (e.g., an engine condition). A central computer receives andprocesses the data from the sensors via the data bus. A modulated signalis transmitted by the transmitter and transmitter via the data bus. Themodulated signal is received at the receiver, the receiver analyzes thereceived modulated signal, and the receiver determines whether anintermittent fault has occurred on the data bus based upon the analysis.The location of the fault may also be determined using any of theapproaches described herein.

In other aspects, a modulated signal is transmitted by one or more ofthe transmitters across a power bus (that is coupled to the sensors).The modulated signal is received at the receiver which analyzes thereceived modulated signal and determines whether an intermittent faulthas occurred on the power bus based upon the analyzing. A location forthe fault may also be determined according to the approaches describedherein.

Referring now to FIG. 1, one example of an approach for determining anddetecting electrical faults in an electrical network 100 is described.An electrical interconnect backbone 102 is coupled to transmitters 104,106, 108, 110, 112, 114 and 116 via electrical branches 120, 122, 124,126, 128 and 130 respectively. The electrical interconnect backbone 102is also connected to a receiver 118. The electrical interconnectbackbone 102 may be any type of electrical connection of any voltagelevel or any current type, e.g., direct or alternating. For instance,the backbone 102 may include two wires (e.g., one ground and the other awire transmitting a DC current and voltage). Other examples of backbonearrangements and any number of electrical wires are possible todistribute electrical power. In one example, electrical sources havingvoltages of approximately 100 vRMS (or 28V DC) are distributed acrossthe backbone 102 and the branches of the network 100.

The transmitters 104, 106, 108, 110, 112, 114 and 116 are any type ofdevice capable of transmitting any type of modulated signal, overelectrical circuit 102 without compromising the power deliveringfunction of the electrical network 102, that includes any type ofinformation. For example, the transmitters 104, 106, 108, 110, 112, 114and 116 may include controllers to form packets or messages, modems toconvert the messages to suitable signals through modulation (e.g.,having the proper voltage levels) for transmission, and a couplingnetwork to provide filtering and protective functions to connect any ofthe transmitters to the electrical interconnect backbone 102. Asmentioned, the transmitters 104, 106, 108, 110, 112, 114 and 116 mayoperate and transmit packets or messages at any voltage levelappropriate for the electrical interconnect backbone 102.

The receiver 118 is any device capable of receiving modulated signalsfrom any of the transmitters 104, 106, 108, 110, 112, 114 and 116 viathe electrical interconnect backbone 102. As with the transmitters 104,106, 108, 110, 112, 114 and 116, the receiver 118 may include acontroller, a modem and a coupling network. As mentioned, the couplingnetwork buffers the receiver or transmitter from the electricalinterconnect backbone 102 by a filtering function so that the receiveror transmitter insulates it from the high voltages of the electricalnetwork while effectively sending and receiving the modulated signal.The modem in the transmitter modulates the digital signal formed by thecontroller and the modulated signal travels through the coupling networkinto the electrical network. The modem in the receiver accepts themodulated signal via the coupling network sent from the transmitters,demodulates the signals into a digital byte format, and sends thedigital data to its controller. The receiver controller processes thesignals for data errors or mismatch to determine whether a fault hasbeen detected or the likelihood that a fault has been detected and/orthe possible location of faults. Various error rates can be determinedfrom the process.

The receiver 118 communicates with a port 132 and the port 132 iscoupled to an external device 134. The external device 134 may be apersonal computer, display, enunciator or any other type of device thatis capable of alerting a user that a fault has been detected somewherein the network 100. The location of faults and message error ratecalculated for the location may also be displayed to give the severity(likelihood) or status of the fault progress. In an alternativeapproach, the external device 134 may provide some or all of the faultdetermination processing capabilities rather than the receiver 118 whenthe receiver 118 is limited to provide the mismatch or error occurrenceonly.

In one example of the operation of the system of FIG. 1, thetransmitters 104, 106, 108, 110, 112, 114 and 116 transmit messages tothe receiver 118. The receiver 118 analyzes the messages that itreceives and based upon the results of the analysis determines whether afault exists, the likelihood that a fault exists, and/or the possible(or determined) location(s) of faults (e.g., within a particular branch120, 122, 124, 126 and 128 or 130 of the network 100). It will beappreciated that although a single receiver is shown in the example ofFIG. 1, any number of receivers may be used in the network 100.Additionally, any number of transmitters may be employed in the network100.

Once errors are detected and/or their locations determined remedialaction can be taken. For example, a user can access the potential siteof the error, determine if a problem exists, and, if a problem existsremedy the problem (e.g., replace a wire). It will be appreciated thatthe system of FIG. 1 can be disposed at any location such as within avehicle (e.g., car, truck, aircraft, or ship), within an appliance, orwithin a building. Further, the system of FIG. 1 can be disposed acrossmultiple locations such as in various types of networking arrangementsor configurations.

Referring now to FIG. 2, one example of a message format for messagestransmitted according to the approaches described herein is described. Amessage or packet 200 includes a preamble byte 202, a receiverinformation byte 204, a transmitter information byte 206, and 4 to mmessage bytes 208 where m is an integer greater than 4. In one approach,each transmitter within the system (e.g., transmitters 106, 108, 110,112, 114, or 116 of FIG. 1) has a uniquely identifiable message byte(e.g., some unique pattern of binary ones and zeros) that is known tothe receiver and that uniquely identifies a transmitter (e.g., thereceiver 118 of FIG. 1). All information in the message or packet 200 isincluded in the data stream that is transmitted to the receiver.

To detect an error or fault, in one approach, the receiver compares thedata received from the transmitter against pre-assigned data that it hasstored regarding each transmitter. In the case of a mismatch between thereceived data and the expected data, a fault is potentially detected.The non-reception at the receiver of an expected message or packetexpected to be sent from the transmitter may also indicate the existenceof a fault in the form of open circuit in the network.

For transmissions across the network, various approaches may be used toensure signal integrity (e.g., to ensure signals sent by multipletransmitters do not interfere with each other). In any approach used,the modem of each transmitter monitors the wire via a “carrier detect”approach that detects if there are any modulated signals on the wire,and waits to send its signal until there is no signal on the wire.Therefore, at any one moment, only one transmitter is allowed to sendsignals. In one approach, multiple transmitters send signals without thecontrol of the receiver. To ensure signal integrity, a random pauseduration is inserted after each signal transmission. Each transmitterhas an equal chance to send a signal to the receiver and, therefore,each wire segment (e.g., each branch of the network) is monitored at thesame priority with an equal chance of detecting errors compared with anyother electrical branch.

In another approach that may be used to achieve signal arbitration, onlya transmitter that is ordered by the receiver is allowed to send asignal. In other words, the receiver is the master of this single-masterand multiple-slave protocol. The receiver sends a message or packet(e.g., a command) to a transmitter, for example, the message of FIG. 2.After the transmitter receives the message or packet from the receiver,this message is copied and sent back to the receiver. The comparison ofthe received message at the receiver against the sent message determinesif there is an error in the signal, which in turn indicates that a faultexists in the wire segment between the receiver and the commandedtransmitter. In some approaches and as described elsewhere herein, anerror is detected if no return message is detected by the receiver(e.g., within a predetermined amount of time), indicating possibledisconnected, open circuit.

Referring now to FIG. 3, one example of using these approaches to detectan error or fault in a network 300 is described. In this example, anelectrical backbone 302 is coupled to transmitters 304, 306 and 308 anda receiver 310. The network 300 is divided into segments S1, S2 and S3and branches Br1, Br2 and Br3. It will be appreciated that the system ofFIG. 3 can be disposed at any location such as within a vehicle (e.g.,car, truck, aircraft, or ship), within an appliance, or within abuilding. Further, the system of FIG. 3 can be disposed across multiplelocations such as in various types of networking arrangements orconfigurations.

A table 312 is stored in a memory at the receiver and used to determinethe possible location or locations of electrical faults within thenetwork 300. For example, using the techniques described herein, it isdetermined if a particular error exists in one of the branchesassociated with a particular transmitter. For example, the mismatch ofexpected data from the transmitter 304 versus expected data, while thereis no mismatch from the transmitters 306 and 308, may indicate that afault exists in branch Br1.

To take a few examples and utilizing the table 312, if no errors aredetermined for transmitters 304, 306 and 308, no fault exists in thenetwork. In another example, if no errors are detected at transmitters304 and 308, but an error is detected at transmitter 306 then a faultmay exist at segment S2 and/or both branches Br2 and Br3. It will beappreciated that the table 312 may be any type of data structure and isalso not limited to the format shown in FIG. 3. Moreover, the examplesshown in table 312 may vary depending upon the placement of thetransmitters and the receiver and the exact configuration of the networkor other circumstances.

Referring now to FIG. 4, one example of a transmitter or receiver 400 isdescribed. The device 400 can be configured to operate as either atransmitter or receiver and includes a controller 402, a modem 404, acoupling network 406, and a memory 408.

If used as a transmitter, the controller 402 may form messages (e.g.,packets) to send to a receiver via the modem 404 and coupling network406. The modem 404 forms signals according to appropriate voltage levelsor protocols and the coupling network 406 provides appropriate bufferingand/or filtering capabilities that protect the modem 404 and controller402 from electrical hazards (e.g., overvoltage conditions) present onthe backbone and, at the same time, effectively inject the modulatedsignals into the backbone.

If used as a receiver, the coupling network 406 filters in only themodulated signal from the backbone and the modem 404 demodulates thesignal into digital data and sends it to the controller 402. As areceiver, the device 400 may store in the memory 408 a table as has beendescribed above with respect to FIG. 3. The controller 402 then mayperform an analysis to determine the potential location or locations offaults within a particular network. Further, the controller 402 may becoupled to a port, which communicates with external devices to indicateto a user the presence and potential locations of faults. Further, thecontroller 402, modem 404, and/or coupling network 406 may be coupled toan external power supply.

Referring now to FIG. 5, one example of a transmission arbitrationprotocol is described. At step 502, a message or packet is sent from atransmitter. For example, the message may be in the format as indicatedin FIG. 2. At step 504, after the message is sent, a random pauseduration is inserted after the message. Then, the same message is sentagain, and this process continues, and to take one example, the receivercompares the received message to the expected message and determinesthat a fault exists if there is a mismatch. When a mismatch exists, apotential fault may exist in the portion of the network associated withthe transmitter that sent the message.

Referring now to FIG. 6, another example of a transmission arbitrationprotocol is described. At step 602, a transmitter waits to receive amessage from a receiver. At step 604, after receiving a message thetransmitter echoes the same message back to the receiver. Then, it waitsfor another command from the receiver. In the meantime, if the receivernever receives an echoed message back (e.g., after waiting for apredetermined time period) or the message returned to the receiver is inerror (as would be indicated by a comparison of the received messagewith the expected message), then a fault (including open circuit) isindicated to exist.

Referring now to FIG. 7, another example of approaches for faultdetermination is described. As shown in FIG. 7, through a couplingnetwork and modem 761, a packet 701 (having pre-set values) is sent fromtransmitters 702, 704, and 705 to a controller 703 of a receiver, andread through serial communication port 736 of the controller 703.

The packet 701 includes, for example, preamble byte 732, and atransmitter identification byte 733, and a packet number byte 734,followed by n data bytes 735, D1 through Dn. N may be any integer value.In one example, n=24 and, consequently, 24 bytes of data are used. Therate of the data transmission, or bit rate, can become any speed or anymodulation scheme suitable for the modem. In the some examples, a 2400bps power line modem is used that provides approximately 130 kHz ofFrequency Shift Keying (FSK) modulation. However, other numbers of databytes may be used along with other bit rates and other modulationschemes. In some examples, a longer packet with slower bit rate with amodulation scheme may have better chance of intermittent fault detectionthan a shorter packet with higher bit rate with another modulationscheme.

The controller 703 of the receiver, after detecting the preamble byte732, followed by identification byte 733, then reads the rest of thebytes (step 760) one at a time and store the packet into internal memoryspace 741. In another part of the memory 741, the packet 701 is storedas a packet 742 and is used for a comparison with an expected (andpreviously stored) packet 743. The expected packet 743 includes theexpected values of information for the packet 742. The packetinformation stored in memory can be compared against each of thetransmitters.

The controller 703 at step 762 reads the stored packets 742 and 743 andmakes a bit-by-bit comparison of all n data bytes against the pre-setvalues of the n data bytes between the packets 742 and 743. The firstanalysis is to decide which transmitter sent the packet and thesubsequent analysis result for packet mismatch is stored and associatedwith the transmitter. If the two packets are the same, then the resultof no error is registered for the transmitter. Then, with for example,the decision table of FIG. 3, a fault detection and location decision ismade and displayed 753 or uploaded to an upper level computer 755. Then,the next packet sent from a transmitter is read at step 762.

At step 764, the error details (including the identity of thetransmitter that sent the packet) may be stored. At step 766 it isdetermined if an adequate number of packets has been received in orderto determine whether an alarm should be given a user. If the answer atstep 766 is negative, control returns to step 760. If the answer isaffirmative, execution continues at step 768 where a comparison is madewith a threshold 770. If the number of erred packets exceeds thethreshold, a result 772 is formed as a fault (e.g., “1”) or no-fault(e.g., “0”) result of a particular transmitter as in the table of FIG.3. The final decision on fault determination using the table (stored inmemory) is made and communicated to one or more of a port 750 (fordisplay on an enunciator 751), a communication port 752 (forpresentation on a display 753) and/or port 754 (for display on apersonal computer 755). Depending upon the type of display, graphicalimages may be formed to be displayed on some or all of the mentionedexternal devices.

As described herein, a pause may be inserted between transmittedpackets. In one example, the pause between two consecutive packets, in asystem using a microcontroller of 8-bits and 20 MHz speed, is about 100milliseconds. The pause time is selected so as to be sufficient forprocessing to occur. For example, the pause duration may be selected toallow for the fault determination process to finish and also for errormessages to be sent to external devices (e.g., the enunciator 751, thedisplay 753, and/or the personal computer 755). The pause duration canalso include time to allow processing to occur for a given number ofpackets, for example, 1000 packets.

The threshold level of the rate of error that initiates the fault (e.g.,“1”) or no-fault (e.g., “0”) can be any predetermined value or,alternatively, be determined after a run of the system under cleanelectrical wire status. Further, the threshold can be automaticallydetermined using the error rate by comparing the error rates duringactual/normal operating status and those of actual intermittent faultstatus. Before deploying the above-mentioned approaches, a test run maybe executed in a staged intermittent fault condition that sets thethreshold level for a fault or no-fault boundary, and thus increases thedetection probability while at the same time decreasing false alarm andnuisance readings.

Various error rates can be determined. For example, a first error typethat can be calculated is a Net Packet Error Rate (NPER), which is thepercentage of packets that contained errors out of the total number ofreceived packets. In the NPER case, the lost packets by the error inidentification byte(s) are ignored.

Alternatively, a Total Packet Error Rate (TPER), can be calculated. Thisrate is the percentage of the number of packets received with error outof the total number packets sent.

In another example, a Net Byte Error Rate (NBER) can be calculated. TheNBER is the percentage of the number of packets received with just 1data byte error caused by 1 or 2 bit errors in the byte out of thereceived packets with no error. The NBER focuses, unlike NPER or TPER,on very short disruptions. Very short disruptions in time rooted from anintermittent fault may cause error in a bit or two in a byte data, notacross the data bytes.

Yet another alternative error rate that can be determined is the TotalByte Error Rate (TBER), which is the percentage of the number of packetsreceived with 1 data byte error caused by 1 or 2 bit errors in the byteout of the total number of packets sent. The TBER ignores anydisruptions which are long enough to cause errors in multiple databytes. This rate does not include or consider long disruptions possiblycaused by normal switching operations and, as such, could reduce thenumber of false alarms.

Referring now to FIG. 8, a receiver 801 receives packets over electricalwires 810 and 811 that are transmitted by a transmitter 802. If theelectrical wire carries DC current, then one of the wires 810 or 811 canbe a ground wire. In the example of FIG. 8, both the receiver 801 andthe transmitter 802 have the same functional structure and includes amodem 802 or 804 and a controller 803 or 805. The receiver 801 includesadditional interface outputs or ports 812, 813 and 814. The output 813is connected to an indicator/enunciator 807 to send an alarm when anintermittent fault is detected. This may be in the form of blinkinglight (e.g., light emitting diode (LED)) and/or audible indication. Theport 813 is used to display the alarm condition on a display 806 (e.g.,a liquid crystal display (LCD)) with texts and graphics. The output 814is further used to send the alarm condition to a computer system 820 viaserial communication port 808 for displaying on a computer screen or forfurther analysis of the alarm condition data. The errors and error ratesdiscussed herein can be displayed according to any of the displayapproaches described herein.

The transmitter 802 includes the modem 804 and the controller 805. Thecontroller 805 is a microcontroller or microprocessor which includescomputing code, controls digital logic, and sends bytes of digital data(e.g., packets). The computing code manages the number of packets sentand how often the packets are sent.

Referring now to FIG. 9, one example of a transmitter 900 is described.A modem 921 in the transmitter 900 receives the serially transmitteddigital data stream from a controller 903, converts the digital data toanalog data, and modulates the analog data in FSK (Frequency ShiftKeying) scheme (in which digital logic 1 is coded to analog signal of acertain frequency and digital logic 0 is to another frequency). Themodulated signal is amplified by an amplifier 922 and sent through acoupler 923, which sends the modulated signals and blocks all othersignals outside the frequency band, to the electrical wires 910 and 911.

The modem 921 may be any commercially available modem chip. The modem921 may include a filter that band passes only the frequency band usedin the particular FSK scheme that is employed. The modem 921 has fourcontrol and data communication lines with the controller 903. Theseinclude RX control 930 for controlling the reception of digital data, TXcontrol 931 for controlling the transmission of digital data, carrierdetect (CD) control 932 for indicating to the controller 903 if and whenthe modem 922 receives a modulated signal from an electrical wire, andRX/TX control 933 for indicating if a digital signal has been receivedand is to be transmitted.

A modulated signal automatically is transmitted from the modem 921 andamplified by the amplifier circuit 922. The amplified modulated signalthen is presented to the electrical wires via a coupler 923, whichpasses the signals of the frequency band and blocks all other signals.The coupler 923, in one example, is a transformer coil 924 withfiltering capacitors 925 and 926. In one approach, the structure of thereceiver is identical (or nearly identical with the receiver havingports to communicate with external devices) with the structure of thetransmitter 900.

Various transmission protocols may be used. For example, a byte of anydata can be sent from the receiver to indicate to the transmitter tosend data.

A packet may be sent to the receiver with various bytes of data. Forexample, a preamble byte may be included. The next byte is sent toidentify the transmitter and the receiver. To take one example, if theidentification byte is a preset data value such as a byte data of10110011, then the receiver checks if the received identification byteis 10110011. If the received identification byte is the same as thepreset data, then the receiver is now ready to receive the data streamthat follows. One or more bytes can be used for identification purposes.

As mentioned, in one example, the group of data bytes including thepreamble, identification, and actual data form a packet. In oneapproach, one packet is transmitted from a transmitter and reception ofthe same one packet made by a receiver. In one approach, the transmittertransmits the same one packet repeatedly, with a pause between twopackets, until, for example, a set number of packets are sent (e.g., 956packets). Then, packet transmission resumes. Under an intermittent faultcondition, the preamble byte may be noised out, or the identificationbyte may be contaminated, then the receiver ignores the packet with thecontaminated identification byte since the packet is interpreted as notmeant to be sent to the receiver. In this case, one packet is lost and apacket error exists.

Referring now to FIG. 10, a controller (e.g., a transmitter or receiver)1002 that is coupled to an electrical network is described. Thecontroller 1002 includes a housing 1004 that encloses various electricalcomponents. These components include a processor and modem 1006, anamplifier 1008, a first capacitor 1010, a transformer 1012, a secondcapacitor 1014, and a third capacitor 1016. The controller 1002 isconnected to electrical wires 1018 at connection points 1020. Thehousing 1004 may be constructed of metal, plastic, or any suitablematerial or combination of materials. The modem 1006 performs variousprocessing functions as described elsewhere herein. And, as used herein,the terms wire or wires indicate any type of electrically ormagnetically conductive pathway.

The capacitors 1010, 1014, and 1016 (along with optional protectiveelements not shown in this example) protect the system from high voltagespikes, short circuit conditions, discharging elements, andadapt/convert the carrier signal (being of low-amplitude high-frequency)for transmission to the electrical system or network. These elementsalso convert signals received from the network. The network, in manyexamples, carries a much lower frequency, high amplitude power signalthat needs to be filtered out so that only the modulated signal can beaccepted, for use by the controller module.

The transformer 1012 includes inductive primary and secondary windingsand provides multiple functions for the system. For example, thetransformer 1012 provides isolation of the controller module andamplification circuitry from the wires 1018; injection of the carriersignal on the wires 1018; extraction of the carrier signal from thewires 1018; filtering of the high-amplitude low-frequency signal of thewires 1018; and the filtering of the harmonics of the carrier signal, toname a few examples.

The primary windings of the transformer 1012 (with a capacitor 1010connected in parallel to the windings) form a band-pass filter. Theinductances of the primary windings and the capacitance of the parallelcapacitor 1010 determine a resonance frequency, which is set to thefrequency of the carrier signal. The secondary windings of thetransformer 1012, along with a series capacitor 1020, form a high-passfilter. This high-pass filter is coupled to or includes two terminals1020, which directly connect to wires 1018 of the electrical system ornetwork to allow high frequency carrier signals received to pass to andfrom the wires 1018 while blocking the low frequency high voltage signalfrom the wires 1018.

Since the two filters (band-pass and low-pass) are positioned inside(i.e., disposed substantially entirely within or entirely within thehousing 1004) the controller module 1002, the controller module 1002 is,in this example, permanently connected via the two terminals 1020 to thewires 1018. In one example, multiple controller modules are used andpermanently coupled to the wires 1018.

Referring now to FIG. 11, another example of a transmitter/receiverconnection to an electrical network is described. A first half-couplermodule 1102 includes a housing 1104 that encloses various components.These components include a processor and modem 1106, an amplifier 1108,a first capacitor 1110, and a first winding 1112 of a transformer 1014.A second half-coupler module 1116 includes a second winding 1118 of thetransformer 1114, a second capacitor 1120, a third capacitor 1122, and aswitch 1124. The second half-coupler module 1116 is connected toelectrical wires 1126 at connection points 1128. The components arehoused in a second housing 1117. The second housing 1117 may beconstructed from metal, plastic, or any other suitable material orcombination of materials.

As shown in the example of FIG. 11, the transformer windings 1112 and1118 are placed within two separate housing units. Alternatively, twoseparate circuit boards (or other separate contiguous circuit formingarrangements) can be used. The primary winding is disposed at or withinthe half-coupler 1102 and the secondary winding is disposed at or withinthe half-coupler 1116 so that one half-coupler forms one half of theline coupler circuit described above and the other arrangement forms theother half of the line coupler circuit.

The switch 1120 can be inserted in the wire-side half-coupler, asillustrated in FIG. 11, so that the half-coupler 1116 can bedisconnected from the wire when fault determination functionality is notneeded. One benefit of using a switch 1124 in the wire-side half-coupler1116 is that when the switch 1124 is in the off (i.e., deactivated)position, no power consumption occurs.

The half-coupler 1102 includes one winding and a parallel capacitor, andthese components are located entirely or substantially entirely withinthe housing 1104 and provide band-pass filtering. The half-coupler 1102does not have output terminals for connection. Instead, its windingbecomes a signal exchange point in the system.

As mentioned when aligned and magnetically linked together, the twohalf-couplers 1102 and 1116 form a coupler circuit and works as acomplete coupler. By the separating the coupler into a wire-sidehalf-coupler 1116 and an in-controller half-coupler 1102, the controlmodule (whether used as a transmitter or receiver) now can becomeportable and is able to wirelessly exchange carrier signals over thewire 1126 via the wire-side half-coupler 1120.

The windings of the half-couplers 1102 and 1120 can be wound around aircore. In another approach, a high permeability split-core (to strengthenthe magnetic linkage and provide efficient magnetic induction of signalof the windings) can be used.

Referring now to FIG. 12, an example of a magnetic coupling arrangementbetween a controller module and an electrical network is described. Afirst half-coupler 1202 includes a first ferromagnetic core 1204 andfirst winding 1206 wound there around. A second half-coupler 1208includes a second ferromagnetic core 1210 and second winding 1212 woundthere around. Various core materials and shapes can be used for optimalsignal exchange. As an example, a ring-shape split core of ferromagneticmaterial can be used with windings at both sides of the split-core asillustrated in FIG. 12.

Referring now to FIG. 13, an example of a magnetic coupling arrangementis described. A first half-coupler 1302 includes a first ferromagneticcore 1304 and first winding 1306 wound there around. A secondhalf-coupler 1308 includes a second ferromagnetic core 1310 and secondwinding 1312 wound there around.

One side or portion of the split-core (with surrounding winding) isdisposed within the wire-side half-coupler, and the other side ofsplit-core and winding can be disposed within the in-controllerhalf-coupler as illustrated in FIG. 13. During signal transmission orreception, the two half-couplers are placed as close as possible. Thesplit core is aligned such that magnetic leakage is minimized formaximum magnetic induction and, thereby, the signal exchange occurringvia the half-couplers remains completely or substantially undistortedand/or not attenuated. In one example, the two half-controllers areplaced 0.04 inches apart. Other placements are possible.

Referring now to FIG. 14, one example of the physical placement of acontroller module (e.g., a transmitter or receiver) is described. A wall1402 covers wires 1404 which are part of an electrical network thatconducts electrical power. A controller module 1406 is magnetically orotherwise coupled to the wires 1404 and hence the electrical network.Any of the techniques described herein can be used to perform thecoupling.

Referring now to FIG. 15, one example of the placement of controllermodules (e.g., transmitters and receivers) within an electrical networkis described. A first electrical branch (e.g., wires) 1502 is coupled toa second electrical branch (e.g., wires) 1504. The first electricalbranch 1502 is coupled to wire-side half-couplers 1506, 1508, and 1510as described herein. The second electrical branch 1504 is coupled towire-side half-coupler 1512. As shown, wire-side half-coupler 1506 ismagnetically coupled to a receiver 1514. The receiver has a contactpoint 1516 where it is magnetically coupled to any wire-sidehalf-coupler (e.g., wire-side half-coupler 1506). A controller 1518includes a contact point 1520 where it is coupled to any other wire sidehalf-coupler (e.g., wire side half coupler 1510).

Any of the wire-side half-couplers can be constructed according tovarious configurations and dimensions, and provide various connectiontypes. For example, a wire-side half-coupler can be a bare circuit board(e.g., no housing) with the winding disposed around a half split-core.

This arrangement also includes a capacitor and a switch. In this case,the switch can be tied to two wires. In another example, the componentsof the wire-side half-coupler can be disposed within a housing. Thehousing may include a cover under which the components (e.g., the coreand winding) are placed. The housing protects the components fromenvironmental conditions or damage caused by bumping, vibrations, or thelike. This wire-side half-coupler operates as a docking place stationfor a half-coupler controller module and the combination of bothhalf-couplers provides carrier signal exchange to and from an electricalnetwork. The housing can be manually connected to wires from its twoterminals (as illustrated in FIG. 15), or it can be inserted to astandardized receptacle outlet of numerous types or any similarconnection mechanism of power point or socket via appropriate connectormechanism attachment at the two terminals. As illustrated in FIG. 15,the wire-side half-couplers can be installed at various locations withinthe electrical network with their switch positions (if the half-couplerincludes a switch) either on or off. The receivers and transmitters canalso be moved between the wire-side half-couplers as needed or required.

The in-controller half-couplers 1514 or 1518 are disposed inside ahousing in such a way that their windings and cores are placed at oneend of the controller housing. Consequently, in docking with a wire-sidehalf-coupler, the in-controller half-coupler is magnetically linked withthe wire-side half-coupler. Multiple numbers of controllers can bepermanently placed in a docked position for continuous operation of thesystem. Alternatively, a controller used as a receiver and dockedpermanently in a location, and a transmitter controller can be movedfrom one wire-side half coupler to another to check for the presence andlocation of intermittent electrical faults from various places in thenetwork. In any of the examples described herein, either of thehalf-coupler modules can have single or multiple primary and secondarywindings.

A transmitter controller module and its winding(s) may be coupled tomultiple wire-side half-couplers. The wire-side half-couplers theninject signals into the electrical network. Thus, by using the portableand wireless carrier signal exchange mechanism described herein, only asingle transmitter is needed to transmit carrier signals to multiplewire-side half-couplers positioned within its range. Thissingle-transmitter controller and multiple wire-side half-couplerconfiguration can be implemented according to several differentapproaches.

In one example implementation, the transmitter controllerindiscriminately broadcasts its carrier signal using a single frequencyband as described herein to any wire-side half-coupler of a frequencyselecting circuit such as a high-pass filtering apparatus. The signalsare injected into the electrical network and any wire-side coupler(acting as a receiver) tuned to the same tuned frequency band receivesthe transmitted information through the wire-side half-coupler to whichit is docked when the electrical system is operating correctly (i.e., nofaults exist). This information is then communicated (via a magneticcoupling) to the receiver controller half-coupler. When any part of theelectrical system is in an intermittent fault condition, one of thereceived data streams will indicate an error, but the receiver may notknow the exact location of the fault condition since the data streamcould be from any one or multiple wire-side couplers. This approachprovides information concerning the general health of the electricalnetwork and the general area where a fault condition exists.

In another approach of implementing the system architecture describedherein, the transmitter controller selectively broadcasts its carriersignal of different frequency bands at different times so that only asingle or a group of wire-side half-couplers tuned to the same frequencyband can receive the carrier signal and, therefore, the carrier signalcan be injected to the wire system through the selected wire-sidehalf-coupler or couplers.

This second approach preferably employs modified half-couplers coupledto the examples discussed above. More specifically, the in-controllerhalf-coupler (of both transmitter and receiver controllers) are able toselectively generate and receive different frequencies and each can betuned to one or a group of wire-side half-couplers. The selectivefrequency filtering and generation can be achieved by deployingprogrammable variable inductors and capacitors that can be controlled bya microprocessor (or similar arrangement) or by placing multiple pairsof inductors and/or capacitors (or other active or inactive electricalcomponents) of suitable values that can be manually selected by user toachieve the desired frequencies. In addition, each wire-sidehalf-coupler is preferably configured to provide a band-pass filteringhalf-coupler, which can be tuned to any desired frequency band. Thus,because a given frequency is generated by the transmitter controller,only one specific wire-side half-coupler or a group of wire-sidehalf-couplers are tuned, thereby allowing the exchange of carriersignals.

In the second approach, the transmitter sends a carrier signal ofdifferent frequency bands at different times (e.g., randomly,sequentially or according to other known approaches), to the wire-sidehalf-couplers within the range of the transmitter. The signal is theninjected into the electrical network. Receivers then selectively receivethe carrier signal from a specific wire-side half-coupler or a group ofwire-side half-couplers, which are used for the carrier signal injectionto the wire system. With different wire-side half-couplers placed inpredetermined locations in the wire system, this approach provides thelocation information of the wire-side half-coupler(s) and the locationof intermittent faults in the wire system. Assigning a specificfrequency to a single wire-side half-coupler or a group of wire-sidehalf-couplers may increase the accuracy level of locating faults in theelectrical system.

The present approaches detect intermittent faults, harbingers topermanent faults to come, in the line circuit existing between atransmitter and a receiver. A carrier signal is injected into thenetwork and any disruption to the signal caused by the intermittentexcursions of voltage and current in the network can be detected. Thelocation or the resolution or accuracy of the location of the system canbe obtained by identifying the wire segment where a transmitter and areceiver are installed to monitor the intermittent events. Multipletransmitters and receivers can be strategically installed to form zonesof circuit, whether it be a single circuit or multiple, branched feedersfrom a circuit. Overhead lines, underground cables, and windings andcoils can be considered wires in these approaches as far as they provideelectricity to loads. Intermittent faults in any of these elements canconsequently be determined.

Many of these approaches inject coded multiple carrier signals frommultiple transmitters to one or more receivers, which act as a basestation for detection and location of faults, in such a manner thatfaults in any zone made of a transmitter at one end and a receiver andthe other end can be identified. Zones can be defined on the maincircuit, feeders, and branches, series or parallel connected. In oneexample of these approaches, a receiver station at the main circuit ispositioned close to the source and a transmitter is positioned at eachfeeder, near a branch-out point or a feeder-end point, or anywhere inbetween. If more accuracy is required, additional transmitters can beinstalled in the feeders. For winding machines, transformer windings canbe treated as a “wire” since the carrier signal can be induced at theother side of the transformer if a signal is injected at one side. Theinternal winding faults, turn-to-turn for example, would disrupt theinjected carrier signal and the induced, received carrier signal wouldcontain errors and mismatches, indicating intermittent event and itslocation between the transmitter and the receiver, which is, in thiscase, is the transformer itself. The other winding machine type, motor,is a load. The noise from loads may also affect the carrier signal overthe wire; therefore, the zone structure is able to determine thelocation of such noisy behavior of a motor load.

In wavelength-division multiplexing (WDM) optical networks, a networknode consists of an optical switch and an electronic controller. Theelectronic controller manipulates the switch, and maintains informationabout the network topology and wavelength occupation. Network nodes areconnected by network links (e.g., optical fibers) that carry a number ofoptical channels. These optical channels carry data. On the other hand,the electronic controllers communicate with each other using dedicatedelectronic or optical channels. The WDM multiples optical carriersignals on a single optical fiber by using different wavelengths oflight to carry different signals, which enables multiple bidirectionalcommunication over one strand of fiber.

In an optical network, faults include breaks or poor connections orsharp bends in an optical fiber, and their effect in data disruptionpropagates in the network links. Data disruption from a single fault canpropagate throughout an entire optical network without revealing theaccurate location of the source of the fault.

Intermittent and permanent fault conditions in optical network (e.g.,breaks, poor connections, or sharp bends in an optical fiber to name afew examples) can be detected by the present approaches of signalinjection, and the presence and location of fault can be found by thesame way of pairing transmitters and receivers as discussed herein withrespect to wired networks, with data mismatches in the pairs. The faultdetection in fiber optic network utilized by the present approaches isdescribed, using two example cases and under two different networksituations: a general optical network and a WDM optical network. Otherexamples are possible.

In optical networks that use general fiber links, where multiplexing maybe or may not be employed, the transmitter controller sends data packetto a modem and the modem modulates the data into high frequency signal,whose wavelength is different from that (or those) of data transmission.For example, as illustrated in FIG. 16, a transmitter 1601 includes afirst controller 1602, a first modem 1604, a first electrical-to-optical(E/O) interface 1606 and a first optical splice 1608. A fiber link 1610connects the transmitter to a receiver. The receiver 1611 includes asecond controller 1612, a second modem 1614, a second O/E interface1616, and a second optical splice 1618. In this example, the differentwavelength signal is then injected via the first E/O interface 1606 andthrough the first optical splice 1608 into an injection point of thefiber link 1610. At the reception point of the fiber link 1610, throughthe second optical splice 1618 from the fiber link 1610 and via thesecond O/E interface 1616, the signal arrives at the second modem 1614and is there converted to data packets. At the receiver 1611, the datamismatch and error, caused by fiber faults and failures, are calculatedfor fault detection over the fiber link 1610 between the injection andreception points of the signal and sent to the second controller 1612.Multiple transmitters can be disposed at different points of the fiberoptic network along with one or more receivers for the detection andlocation of fiber faults and failures. By injection and reception ofsignal with a wavelength that is different from the wavelengths used forcarrying data on the fiber link, the present approaches can be utilized,in the same fashion as in wired network, to perform continuousmonitoring of optical network without interrupting the flow of data.

In a WDM optical network, another example of the present approaches canbe used. Since the WDM allows multiple wavelength signals to betransmitted, instead of injecting a different wavelength signal fromthose assigned for data transmission, an unused wavelength signal can beused for fiber channel status monitoring by sending and receiving knownsets of data packets between optical nodes. For example, as depicted inFIG. 17, a system includes a transmitter controller 1702, a firstelectronic controller 1704 and a first optical switch 1706 (together afirst optical node 1701), a second electronic controller 1708 and asecond optical switch 1710 (together a second optical node 1711), and areceiver controller 1712.

In this example, the transmitter controller 1702 as described herein,with established communication to the first electronic controller 1704of the first optical node 1701, commands the first electronic controller1706 to send data packets using an unused wavelength signal. Thereceiver controller 1712 of the present approaches, with a communicationlink to the second electronic controller 1708 of the second optical node1711, commands the second electronic controller 1708 to receive the datapacket transmitted using the unused wavelength signal, and receives thedata packet. At the receiver controller 1712, the data mismatch anderror caused by fiber faults and failures are calculated for faultdetection over a fiber link 1714 between the nodes 1701 and 1711 thatcarry the additional, unused wavelength signal. Multiple transmitterscan be disposed at different nodes of the WDM network along with one ormore receivers in order to detect and locate fiber faults and failure ofbreak, poor connection, and sharp bends in the entire optical network.By using a wavelength that is different from the wavelength used forcarrying data on the WDM network, the present approaches can beutilized, in the same fashion as in wired network, to perform continuousmonitoring for fiber link fault detection in WDM optical network withoutinterrupting the flow of data.

Thus, approaches are provided to detect the presence and locations offaults within an existing electrical network or other type of network.The approaches utilize one or more transmitters to send signals (e.g.,packets) to one or more receivers and based upon the signal received atthe receiver, to determine the presence and location of electrical orother types of faults.

The coupling arrangements described herein can also be split into twohalf-couplers. By separating the coupler into, for example, a wire-sidehalf-coupler and an in-controller half-coupler, the controller now canbecome portable and wirelessly exchange carrier signal with theelectrical system or network via the wire-side half-coupler. Theapproaches described herein are easy and cost effective to use, do notrely upon the transmission of high voltage signals, can be implementedat any place within the electrical system, and are not susceptible tofalse results as have been obtained in previous approaches.

The approaches described herein apply to any type of wired communicationincluding both data lines (e.g., data buses) and power lines. Further,the approaches can be applied to networks that are disposed in anylocation (e.g., vehicles, buildings, local area networks, wide areanetworks no mention a few examples).

Referring now to FIG. 18, one example of a system for detecting and/orlocating faults in various types of networks is described. A building1802 (such as a nuclear power plant, school, or business to mention afew examples) has various elements disposed therein. For instance, apower bus 1808 includes branches 1803, 1805, 1807, and 1809. The powerbus 1808 is coupled to a power source 1804, a first transmitter 1806, adoor sensor 1812, a temperature sensor 1814, a radioactivity sensor1816, a second transmitter 1820, a first receiver 1832, a user interface1824, and a central computer 1828. In this particular example, thebuilding 1802 is a containment building and includes a nuclear reactor1822. A data bus 1810 is coupled to the door sensor 1812, thetemperature sensor 1814, the radioactivity sensor 1816, a thirdtransmitter 1834, a fourth transmitter 1826, a second receiver 1830, theuser interface 1824, and the central computer 1828.

In other examples, the network may be included in a vehicle (i.e., thebuilding 1802 may be a vehicle). When the element 1802 is a vehicle, itmay be any type vehicle such as an aircraft, boat, ship, or vehicle(car, truck, motorcycle, bicycle and so forth). Further, the element maybe an appliance such as a generator or consumer appliance. Stillfurther, the elements residing within the entity 1802 may in someexamples be disposed outside element 1802 (e.g., when the elements areconfigured in a local area network or a wide area network to mention twoexamples). It will also be appreciated that the sensors used in thesedifferent configurations may change to suit the needs of the entity. Forexample, when the configuration of FIG. 18 is disposed in a vehicle, thesensors 1812, 1814, and 1816 may sense the interior temperature of thevehicle, whether a door is open, and tire pressure to mention a fewexamples.

The system of FIG. 18 allows communications to be exchanged between thedifferent entities coupled to the data bus 1810. For example, the userinterface 1824 may communicate with the central computer 1828. Varioususers may use communication devices (not shown) that also couple to thedata bus and exchange information.

A power bus 1808 is any single or multiple conductors that conduct powerto the various system elements. The power source 1804 is any type ofpower source such as an alternating current power source (e.g., agenerator) or a direct current source (e.g., a battery). Other examplesare possible.

The transmitters 1806 and 1820 may be any type of apparatus used totransmit a modulated signal to detect intermittent faults on the powerbus. In one example, the transmitters 1806 and 1820 are the transmittersdescribed with respect to FIG. 4 described elsewhere herein.

The door sensor 1812 is any type of sensing device that can determinewhether a door is open or closed. The temperature sensor 1814 is anytype of sensor (e.g., a thermometer) that can determine the airtemperature of the building. The radioactivity sensor 1816 is any typeof sensor that can determine the radioactivity levels of the building.As mentioned, it will be understood that the sensors 1812, 1814, and1816 are examples only for a building that houses a nuclear reactor andthat the type of sensor that is used may be changed to suit the buildingtype. Further, it will be appreciated that when the system is integratedinto a vehicle the type and function of the sensors will also likely bechanged. The sensors may be attached to a building element (e.g., wall,beam, door, window, ceiling, to mention a few examples) so that they cansense a condition (e.g., temperature) or status (e.g., door open, doorclosed) in the building, associated with the building, or associatedwith a building element. When used in a vehicle, the sensors may beattached to the vehicle or vehicular element (e.g., on the door frame,in the interior), to detect various conditions (e.g., a door being open,or interior temperature).

The receiver 1832 may be any type of apparatus used to receive amodulated signal to detect faults. In one example, the receiver 1832 isa receiver as has been described with respect to FIG. 4 describedelsewhere herein.

It will be appreciated that the various transmitters and receiversillustrated in FIG. 18 may be integrated into any of the other devicesshown in FIG. 18. For example, some of the transmitters and/or receiversmay be integrated with (i.e., included within the housing of) otherdevices such as the central computer 1828 or the user interface 1824. Inone example, a receiver 1838 is integrated with the central computer1828.

The user interface 1824 is any type of device used to presentinformation to a user and/or receive user input. For example, the userinterface 1824 may be a personal computer, laptop, cellular phone,personal digital assistant, or pager, to mention a few examples. Otherexamples of interfaces are possible. In the example of FIG. 18, whencoupled with receivers such as 1832 on the power bus and 1826 on thedata bus (indicated in dashed lines), the user interface 1824 may beused to display alarms to a user when an intermittent fault is detectedat either or both of the buses. The interface 1824 may also be used toshow the location of the fault to users. It will be appreciated that theformat used to display information to the user may be changed andadjusted to suit the needs of the user and the system. The userinterface 1824 (and/or the receivers) may be coupled to other systems byany type of wired (e.g., internet) or wireless connection.

The central computer or controller 1828 is any type of processing devicethat is configured to receive and process information from the sensorsand/or the user interface, and it may be coupled with the receivers suchas the receiver 1830 for the data bus and the receiver 1838 for thepower bus (indicated in dashed lines), and may receive information fromone of the receivers indicating a fault and issue warnings to the users(e.g., issues alarm messages). The central computer 1828 may beadditionally coupled to other systems by any type of wired (e.g.,internet) or wireless connection. In a similar manner, receiver 1826and/or 1832 may be coupled to other systems. The central computer 1828or receivers 1830 or 1832 may be communicatively coupled to othernetworks or outside entities using either wired or wireless connections.In this respect, these elements may communicate with outside users(e.g., the police, fire department and so forth) and alert these outsideusers when an intermittent fault is determined. A receiver 1850 may becoupled to a reactor safety system associated with the reactor 1822 andused to activate reactor safety controller to switch to a stand-by powerbus and to call for immediate maintenance on the power bus (e.g., whenan intermittent fault is determined). The central computer 128 mayinclude a data base or memory to store various types of information.

The data bus 1810 is any type of data base that can be used to transmitinformation between electronic devices. The data bus 1810 may be singleor multiple wires. The type of wire may be metal, fiber optical cable tomention two examples.

The transmitters 1826 and 1834 may be any type of apparatus used totransmit a modulated signal to detect faults. In one example, thetransmitters 1826 and 1834 are the transmitters described with respectto FIG. 4 as described elsewhere herein.

The receiver 1830 may be any type of apparatus used to receive amodulated signal to detect faults. In one example, the receiver 1830 isa receiver as has been described with respect to FIG. 4 as describedelsewhere herein.

In one example of the operation of the network in FIG. 18, dataassociated with at least one building condition or status is sensed byone or more of the sensors 1812, 1814, or 1816. The data from thesesensors may be sent over the data bus 1810 and received by the centralcomputer 1828. In addition, a modulated signal may be transmitted by oneor both of the transmitters 1834 or 1826 across the bus 1810. Themodulated data signal is received at the receiver 1830, which analyzesthe received modulated data signal, and determines whether anintermittent fault has occurred on the data bus based upon theanalyzing. For example, the receiver 1830 may compare the receivedsignal to an expected pattern and when a discrepancy exists, anintermittent fault is determined to exist. The receiver 1830 may alsodetermine the location of the fault based upon the analysis usingapproaches that have been described elsewhere herein.

In other aspects, intermittent power bus faults are also detected. Inthis respect, a modulated power signal is transmitted across the powerbus 1808 by the transmitter 1806 and/or the transmitter 1820. Themodulated signal is received by the receiver 1832 and the receiver 1832analyzes the received modulated signal and determines whether anintermittent fault has occurred on the power bus 1806 based upon theanalysis. For example, the receiver 1832 may compare the received signalto an expected pattern and when a discrepancy exists, an intermittentfault is determined to exist. The receiver 1832 may also determine thelocation of the fault based upon the analysis according to theapproaches described herein.

In this example, the modulated signals are transmitted from multipletransmitters to a single receiver. Other configurations are possible.

In still other aspects, a modulated carrier signal is transmitted by oneof the transmitters 1826 or 1834. When the modulated carrier signal isreceived at the receiver 1830 without significant distortion at thereceiver 1830, a data signal is transmitted from one of the sensors1812, 1814, or 1816 or central computer 1828, or user interface 1824,over the data bus 1810. The data signal is received at the receiver 1830and the received data signal is analyzed by the receiver 1830 todetermine if an intermittent fault exists on the data bus 1810 (e.g., bycomparing it to an expected pattern). The result obtained by thereceiver 1830 may be communicated to the central computer 1828 via thedata bus 1810 or via some other approach (e.g., a wireless connectionfrom the receiver 1830 to the central computer 1828). Alternatively orin addition, the result may be communicated either across a wiredconnection or wirelessly to an external device or system at anotherlocation (e.g., the police, a central dispatch center, to mention a fewexamples). Action that can be taken to correct the fault (e.g.,replacing the wire).

In another example, a data signal is sent from a transmitter to areceiver. The data signal is sent back from the receiver to the originaltransmitter. The transmitter compares the signal to what was sent and ifthere is no discrepancy, a data signal is sent over the data bus (i.e.,there is no fault). Otherwise, a fault is determined to exist.

In yet other aspects, the sensing device may be a temperature sensor, aradioactivity sensor, a motion sensor, a pressure sensor, or a humiditysensor. Other examples of sensors or sensing devices are possible.

In another example of the operation of the system of FIG. 18, one ormore of the sensors 1812, 1814, and 1816 (that are disposed in thebuilding 1802) sense a condition or status associated with the building1802. A plurality of modulated signals indicating this information aretransmitted across the data bus 1810 that is disposed in the building1802. Each of the plurality of modulated signals is modulated accordingto an approach that avoids interference between each of the plurality ofsignals. The plurality of modulated signals from the sensors 1812, 1814,and 1816 are received, for example, at the central computer 1828, andthe central computer 1828 processes the data in the received modulatedsignals.

In other aspects, a modulated signal is transmitted from the transmitter1834 or 1806 and across the power bus 1808 that is coupled to thesensors 1812, 1814, or 1816. The modulated signal is received at thereceiver 1832. The receiver 1832 analyzes the received modulated signaland determines whether an intermittent fault has occurred on the powerbus 1808 based upon the analysis. A similar approach can be used on thedata bus 1810 to determine if intermittent faults are present on thedata bus 1810.

Various forms of modulation may be used to avoid interference betweensignals. For example, amplitude shift keying (ASK) modulation, frequencyshift keying (FSK) modulation, Phase shift keying (PSK) modulation,Binary shift keying (BSK) modulation, Binary Phase shift keying (BPSK)modulation, quadrature phase shift keying (QPSK) modulation, offsetquadrature phase shift keying (OQPSK) modulation, minimum shift keying(MSK) modulation, Gaussian minimum shift keying (GMSK), multiple phaseshift keying (M-PSK), QPSK modulation may be used. Other examples ofmodulation approaches may be used to modulate power and/or data signals.

In another example of the operation of the system of FIG. 18, the entity1802 is not a building but a vehicle and one or more of the sensors1812, 1814, or 1816 (disposed in the vehicle) sense data and the data isassociated with at least one condition or status associated with thevehicle 1802. In this respect, the sensors 1812, 1814, and 1816 maysense interior vehicle temperature, door status (open or closed), andtire pressure. The central computer 1828 receives and processes the datafrom the sensors via the data bus 1810. A modulated signal is formed andtransmitted by the transmitter 1826 and transmitter 1834 across the databus 1810. The modulated signal is received at the receiver 1830 and thereceiver 1830 analyzes the received modulated signal and determineswhether an intermittent fault has occurred on the data bus based uponthe analyzing. The location of the fault may also be determined via anyof the approaches described herein. As described elsewhere herein, theapproaches described herein are not limited to vehicles or buildings butcan be applied to networks of any size disposed at any location orlocations. For instance, some or all of the elements of FIG. 18 may bedisposed in an appliance, in a local area network, or a wide areanetwork to mention a few examples.

In other aspects, a modulated signal is transmitted by one or more ofthe transmitters 1806 and 1834 across the power bus 1808 (that iscoupled to the sensors). The modulated signal is received at thereceiver 1832 which analyzes the received modulated signal anddetermines whether an intermittent fault has occurred on the power busbased upon the analyzing. A location for the fault may also bedetermined according to the approaches described herein.

Referring now to FIG. 19, one approach of using single receiver fordetermining intermittent faults at both a data bus 1903 and a power bus1905. The receiver 1906 may be equipped with two appropriate couplers(e.g., as described elsewhere herein) for each of the data and powerbuses and applied with the same or different modulation method with thesame or different frequency in such a way that the modulated signal oneither bus does not create interference with the data or power signals.The coupler and modulation method and frequency of the receiver 1906 forthe data bus 1903 may be the same to those of a transmitter 1902 on thedata bus 1903, and the coupler and modulation method and frequency ofthe receiver 1906 for the data bus 1903 must, in one example, be thesame or equivalent to those of a transmitter 1904 on the power bus 1905.To provide various applications, one or more sensors 1910, one or moreprocessors 1912, and one or more indicators 1914, for example, areconnected to the data bus 1903 at one side and to the power bus 1905 atthe other side.

Referring now to FIG. 20, at step 2002, a transmitter sends a modulatedsignal 2003 across a data bus. On the data bus, there may be varioustypes of information that may be processed by a processing unit, forexample, indicating the physical conditions of a vehicle or building.The processing may result in actions be requested for a user to comply(e.g., increase the temperature, close the door, to mention a fewexamples). Multiple signals may be sent from multiple transmitters.

At step 2004, a transmitter sends a modulated signal 2005 across thebus. Multiple signals may be sent from multiple transmitters. At step2006, the modulated signal is received at a single receiver unit (oralternatively, multiple receiver units) coupled for both types ofmodulated signals.

At step 2008, the receiver compares the modulated signals to apredetermined pattern for each of the both signals. For example, a testpattern stored in a memory may be compared to the received signal.

At step 2008 a determination is made whether an intermittent faultexists on either of the buses and a location for the intermittent faultmay also be determined according to the approaches described herein.Otherwise, no intermittent fault is determined to exist. At step 2012,an alert is sent to a user. This information may be presented at anysuitable user interface such as a personal computer. The determinationthat a fault exists and the location of the fault may also be sent tosome other entity (e.g., a control center, a dispatch center, thepolice, the fire department, to mention a few examples).

Referring now to FIG. 22, another approach for determining intermittentfaults is described. This can be used in both a data bus (data lines)and a power bus (power lines). At step 2202, a transmitter sends amodulated carrier signal 2203 across a data bus. At step 2206, a datasource (e.g., sensor) sends a data signal 2205 across the bus. The datasignal 2205 transmitted may include various types of information thatmay be processed by a processing unit, for example, indicating thephysical conditions of a vehicle or building.

At step 2204, the modulated carrier signal is received at the singlereceiver (or, alternatively, multiple receivers may be used). At step2208 it is determined if the modulated carrier signal is distorted. Ifthe answer is negative, execution ends. If the answer is affirmative, atstep 2210 a comparison is made between a data signal 2205 and apredetermined signal (e.g., a predetermined pattern).

At step 2212 an error is determined and a location for the error may bedetermined. Otherwise, no error is determined. At step 2214, an alert issent. This may be presented at any suitable user interface such as apersonal computer. The determination that a fault exists and thelocation of the fault may also be sent to some other entity (e.g., acontrol center, a dispatch center, the police, the fire department, tomention a few examples).

As mentioned, various modulation approaches can be used. Referring nowto FIG. 21, various approaches are described. These approaches allowsignals transmitted by the transmitters 1806, 1834, 1826, 1830 (asdepicted in FIG. 18) from not interfering with each other. Theseapproaches also allow signals from the various sensors from notinterfering with each other.

A digital signal 2102 is to be transmitted from a transmitter (e.g., oneof the transmitters 1806, 1834, 1826, 1830 shown in FIG. 18). Thedigital waveform 2102 shown in FIG. 21 a may be modulated into an ASKwaveform, a FSK modulated waveform 2106, or a PSK modulated 2108.

As used herein “modulation” means facilitating the transfer ofinformation over any type of wired medium. In ASK modulation, theamplitude of the carrier is changed in response to information and allelse is kept fixed. A first bit may be transmitted from a transmitter bya carrier of one particular amplitude. To transmit a 0 bit, theamplitude may be changed (with the frequency held constant) as shown inFIG. 21 b.

In FSK modulation and as shown in FIG. 21 c, the frequency is changed inresponse to information. More specifically, one particular frequency fora 1 and another frequency for a 0. In this example, FSK(t)=sin(2Πf1t)for a 1 is used, and sin(2Πf2t) for a 0 is used.

In PSK modulation and as shown in FIG. 21 d, the phase of the sinusoidalcarrier is changed to indicate information. The term “phase” as usedherein refers to the starting angle at which the sinusoidal waveformstarts. To transmit a 0 bit, the phase of the sinusoidal waveform isshifted by 180°. Phase shift represents the change in the state of theinformation in this case.

As already mentioned, it will be appreciated that various modulationapproaches can be used. For example, amplitude shift keying (ASK)modulation, frequency shift keying (FSK) modulation, Phase shift keying(PSK) modulation, Binary shift keying (BSK) modulation, Binary Phaseshift keying (BPSK) modulation, quadrature phase shift keying (QPSK)modulation, offset quadrature phase shift keying (OQPSK) modulation,minimum shift keying (MSK) modulation, Gaussian minimum shift keying(GMSK), multiple phase shift keying (M-PSK), TU4 QPSK modulation may beused. Other examples of modulation approaches are possible.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention.

1-13. (canceled)
 14. A communication network disposed in a vehicle, thenetwork comprising: a data bus; a power bus; a first transmitter forsending a first modulated signal along the data bus; a secondtransmitter for sending a second modulated signal along the power bus;at least one sensing device coupled to the data bus and the power bus,the at least one sensing device configured to sense data associated withat least one condition or status associated with the vehicle; a dataprocessing module that is connected to the data bus and the power bus,the data processing module being configured to receive and process thedata from the at least one sensing device; an error determinationapparatus spatially separated from the first transmitter and the secondtransmitter and that is coupled to the data bus and the power bus, thebus error determination apparatus being configured to receive the firstmodulated signal and the second modulated signal, analyze the firstmodulated signal and second modulated signal and determine whether anintermittent fault has occurred on the data bus or the power bus basedupon the analysis and not based upon any reflection of the firstmodulated signal on the data bus or reflection of the second modulatedsignal on the power bus, wherein the analysis compares the receivedfirst modulated signal to a first expected data pattern and the receivedsecond modulated signal to a second data expected pattern.
 15. Thenetwork of claim 14 wherein the vehicle is selected from the groupconsisting of a car, a truck, a ship, and an aircraft.
 16. (canceled)17. The network of claim 14 wherein the at least one sensing device isselected from the group consisting of: a temperature sensor, aradioactivity sensor, a motion sensor, a pressure sensor, a humiditysensor. 18-25. (canceled)
 26. A method of determining the existence ofan intermittent fault in a network in a vehicle, the method comprising:sensing data by at least one sensing device disposed in the vehicle, thedata being associated with at least one condition or status associatedwith the vehicle; receiving and processing the data from the at leastone sensing device; transmitting a plurality of first modulated signalsacross the data bus from a first transmitter, receiving the plurality offirst modulated signals at a single receiver, analyzing the receivedplurality of first modulated signals, and determining whether anintermittent fault has occurred on the data bus based upon the analyzingand not based upon any reflection of the first modulated signal on thedata bus transmitting a second modulated signal across a power bus froma second transmitter that is coupled to the at least one sensing device,receiving the second modulated signal at the single receiver, analyzingthe received second signal, and determining whether an intermittentfault has occurred on the power bus based upon the analyzing and notbased upon any reflection of the second modulated signal on the powerbus, wherein the analyzing compares the received first modulated signalto a first expected data pattern and the received second modulatedsignal to a second expected data pattern.
 27. (canceled)
 28. The methodof claim 26 wherein the analyzing comprises comparing the receivedmodulated data signal to a predetermined pattern.
 29. The method ofclaim 26 wherein the at least one sensing device is selected from thegroup consisting of: a temperature sensor, a radioactivity sensor, amotion sensor, a pressure sensor, a humidity sensor.
 30. The method ofclaim 26 wherein the vehicle is selected from the group consisting of acar, a truck, a ship, and an aircraft.